Higher mobility of plutonium in peat compared to uranium
A study on the mobility of actinides in peat carried out by JRC scientists and partners revealed plutonium has migrated downwards to a much larger extent than uranium reaching layers corresponding to the pre-nuclear age. The analysed peat core was collected from an undisturbed ombrotrophic peat bog, receiving water only from atmospheric precipitation. It represents an excellent sample for the investigation of radionuclides from stratospheric weapon tests fallout. The results are important to evaluate the risks associated with other kinds of nuclear contamination, like those of nuclear accidents or releases from nuclear facilities and nuclear waste disposal repositories.
The findings of JRC scientists and fellow colleagues from the University of Alberta, Canada and the University of Vienna, Austria, were released in the scientific journal Environmental Science: Processes & Impacts, published by the UK's Royal Society of Chemistry. The study provides a basis for conducting more detailed assessments of the behaviour and transfer of uranium and plutonium in the environment.
The study was carried out on peat core from Wildseemoor, a protected natural reserve in Germany, which receives all of its water and nutrients from precipitation, rather than from streams or springs. It analysed uranium (236U) and plutonium isotopes (239Pu, 240Pu, 241Pu and 242Pu) using clean room procedures and accelerator mass spectrometry (AMS). This sophisticated analytical approach was ultimately needed to reliably detect the Pu concentrations present in the peat samples at femtogram (10-15 g) and attogram (10-18 g) levels. The long-lived radionuclides contribute to a large body of knowledge on processes involving atmosphere, oceans, ice sheets, biosphere, soils and sediments.
- Paper: Measurements of 236U in Ancient and Modern Peat Samples and Implications for Postdepositional Migration of Fallout Radionuclides
- Paper: Determination of 239Pu, 240Pu, 241Pu and 242Pu at femtogram and attogram levels – evidence for the migration of fallout plutonium in an ombrotrophic peat bog profile